I'm sorry, but that is not TYPICAL behaviour in my opinion. I don't tolerate any kicking, hitting or biting and remove the child who is misbehaving immediately and put them in time out again and again and again and talk to them about NOT doing it anymore. Especially if they are almost age 2 or over becasue they understand what you are saying. You have to be consistent and you have to make sure the parents are punishing the child at home and reinforcing your rules.